Apply subsetting to a time series — apply

This is an internal function that applies a subsetting function to a timeseries. It is somewhat complex, due to way it is designed to be called. The subset is designed to be passed either as a value (NULL or logical), as a expression, or as a variable holding an expression. When it is an expression, it is applied in the context of the timeseries data frame to generate a vector of booleans for subsetting. The complexity comes from the way this implements lazy evaluation, so we cannot evaluate the expression in the normal calling context.

The function also removes row names, and converts the series column to row names.

Usage

apply_subset(timeSeries, subset, env = parent.frame())

Arguments

timeSeries: a time series data frame
subset: (default NULL) either NULL, which selects all entries, or a logical, which TRUE selects all entries and FALSE none of them, or an expression, which will be evaluated in the context of the dataframe to generate a subsetting vector.
env: the calling environment for variable values.